/*
 * sbcs.c - routines to handle single-byte character sets.
 */

#include "charset.h"
#include "internal.h"

/*
 * The charset_spec for any single-byte character set should
 * provide read_sbcs() as its read function, and its `data' field
 * should be a wchar_t string constant containing the 256 entries
 * of the translation table.
 */

void read_sbcs(charset_spec const *charset,
               long int input_chr,
               charset_state *state,
               void (*emit)(void *ctx, long int output),
               void *emitctx)
{
  const struct sbcs_data *sd = charset->data;

  UNUSEDARG(state);

  emit(emitctx, sd->sbcs2ucs[input_chr]);
}

void write_sbcs(charset_spec const *charset,
                long int input_chr,
                charset_state *state,
                void (*emit)(void *ctx, long int output),
                void *emitctx)
{
  const struct sbcs_data *sd = charset->data;
  int i, j, k, c;

  UNUSEDARG(state);

  /*
   * Binary-search in the ucs2sbcs table.
   */
  i = -1;
  j = sd->nvalid;
  while (i + 1 < j) {
    k = (i + j) / 2;
    c = sd->ucs2sbcs[k];
    if (input_chr < sd->sbcs2ucs[c])
      j = k;
    else if (input_chr > sd->sbcs2ucs[c])
      i = k;
    else {
      emit(emitctx, c);
      return;
    }
  }
  emit(emitctx, ERROR);
}
